(1) Background: Sleep patterns are frequently disrupted in neurodegenerative disorders such as Huntington disease (HD); however, they are still poorly understood, especially their association with clinic features. Our study aimed to explore potential correlations between sleep features and motor, cognitive, behavioural and functional changes in manifest HD subjects. (2) Methods: We enrolled 42 patients who were assessed by the Pittsburgh Sleep Quality Index (PSQI) and Insomnia Severity Index (ISI) questionnaires; clinical features were evaluated by the validated ENROLL-HD platform assay, including the Unified Huntington’s Disease Rating Scale (UHDRS) and the Problem Behaviours Assessment Short Form (PBA-s). (3) Results: We found a significant association between the patients’ perception of sleep abnormalities and scores of impaired independence, cognitive and motor performances. Specifically, sleep efficiency (PSQI—C4 subscores) and the use of sleep medications (PSQI—C6 subscores) seem to be more frequently associated with the severity of the disease progression. (4) Conclusion: sleep abnormalities represent an important part of the HD clinical profile and can impair patients’ quality of life by affecting their level of independence, cognition performance and mental well-being.